National Academy of Sciences (NAS)

The National Academy of Sciences is a private agency that advises the
federal government on scientific and technical matters. It is part of the
National Academy, which also includes the National Academy of Engineering,
the Institute of Medicine, and the National Research Council.

The NAS updates and publishes the
Recommended Dietary Allowances
(RDAs), which "represent the
nutrient
intake that is sufficient to meet the needs of nearly all healthy people
in an age and gender group" (Wardlaw). More specific
recommendations are needed for special populations, such as pregnant
women, the elderly population, and those with medical conditions.

In addition, since all nutrients and food components do not have
established RDAs,
Dietary Reference Intakes
(DRIs) were developed as a guide to adequate and safe standards for
nutrients such as
fiber
,
antioxidants
, and
trace
elements, and for upper level intakes of
vitamins
and
minerals
.